The first voltage measurement step S100 is a step for measuring each voltage of a plurality of battery cells. The voltage of each battery cell is measured to calculate a voltage value of each cell. At this point, the calculated voltage value of each cell will be referred to as a first measurement voltage value and a description thereabout will be provided.

The first voltage measurement step S100 may be a step performed by the voltage measurement unit 120. As described above in relation to FIG. 2, the voltage measurement of each cell may be performed in a preset constant period interval.

In other words, the first measurement voltage value calculated by the first voltage measurement step S100 means a voltage value measured in a current period N.

The first overvoltage determination step S200 may be a step for comparing the first measurement voltage value of each cell measured in the first voltage measurement step S100 with a prescribed first reference voltage value to determine whether the cell is overvoltage through a comparison result. As the comparison result, when the first measurement voltage value is equal to or greater than the prescribed first reference voltage value, the corresponding cell is determined to be overvoltage.

The first overvoltage determination step S200 may be performed by the first control unit 130 as described above with reference to FIG. 2.